Bag pressure indicator for suction cleaners



Dec. 26, 1939. D. c. GERBER BAG PRESSURE INDICATOR FOR SUCTION CLEANERS Filed Dec. 5, 1938 Dale 6. Gerber W '5." M

ATTORNEY Q Patented Dec. 26, 1939 BAG PRESSURE mmca'roit FOR SUCTION CLEANERS Dale C.- Gerber, North Canton, Ohio, assignor'to The Hoover Company, North Canton, Ohio, a

corporation of Ohio 1 Application December 5, 1938, Serial No. 244,006

6 Claims This invention relates to improvements in bag pressure indicators for suction cleaners and-more particularly to an indicator designed to register the increased pressure within the dirt or filter bag of a suction cleaner, and for the purpose of warning the operator when the contents of the bag should be emptied.

The object of the invention is to provide a comparatively simple and inexpensive type of pressure indicator characterized primarily by the fact that it is carried directly by the bag and responds. to the variations in pressure therein by'yieldingly resisting the tendency of the bag to expand as the internal pressure is increased. And a further object of the invention is to provide a type of bag pressure indicator which is not only carried by the bag but has detachable mounting thereon so that as one bag becomes worn and discarded,'the indicator can be removed therefrom and attached to a new bag.

A preferred embodiment of the bag pressure indicator hereinabove described, will now be disclosed in connection with the accompanying drawing, in which:

Figure 1 is a perspective view of a suction cleaner showing the location and general arrangement of the indicator;

Figure 2 is an enlarged view in perspective of the indicator removed from the bag and with sections broken away to show its construction; an

Figure 3 is a detailed viewtakenin cross section through the bag at the point of attachment l of the indicator and showing the relative positions of its telescoping'parts under normal and excessive pressure conditions.

The suction cleaner shown in Figure 1 is representative of a standard type of cleaner consisting generally of a wheeled casing I provided with a 4 o plvotally mounted handle 2 by which the cleaner is maneuvered over the floor surface. The casing l houses the usual suction-creating means including a motor-driven fan rotating at high speed within a fan chamber communicating with a downwardly facing nozzle extending across the :iorward end of the casing I.

also has an exhaust or discharge passage leading rearwardly and opening into dirt bag '3 having detachable connectionat its lower end witha flanged outlet connection 4. The upper end of the dirt bag 4 is attached to the handle 2 through the medium of a detachable fastener which permits the bag to .be quickly removed from time to time-for the purpose of emptying its contents.

65 The dirt bag 3 is preferably constructed of a The fan chamber 1 suitable fibrous material of a porous-nature capable of filtering out the dirt particles by permitting the passage of the air therethrough. A fabric woven especially for the purpose, is'prObabIy' {the most satisfactory and durable bag material, 5

although it is to be understood that other materialsmay also be used. a

v The dirt bag is preferably elongated in the di-' rection of the handle beneath which it is located.

Under normal conditions, the bag is distended, 1o

but the pressure created is not sufilcient to effect the operating efliciency of the cleaner. However, if the bag becomes so filled with dirt that p the passage of air through the fabric is restricted, it follows that the internal pressure will in- 15 I crease with a resulting increased back pressure on the suction-creatingsystem and a reduction in its operating efficiency.

The present typeof indicator is designed to respond directly 'to the increased pressureand go the accompanying expansive tendency. but mas-- much as the bag material is not inherently elastie, the same effect is obtained by introducing a slight excess of the bag material between the points of attachment of the indicator to the bag. 2

Considering the. indicator as a unit separate from the bag, the same comprises two endwise extensible metal sections 5 and 6, having overlapping or telescoping engagement throughout their central portions and held together by in- 30 terloclring their side edges and against endwise extension by means of a spring I. These telescoping sections 5 and 6 have the form of elongated plates of thin metal, upset along their longitudinal central portions to provide narrow raised panels and a downwardly facing cavity intended primary to' provide space for the sprin I. In the normal position of the indicator, the

outermost section 5 almost completely encloses the innermost section 6 and inwardly from its free end there is provided a rectangular opening 541 through which the raised central panel of the inner section} is visible. The outer end portion of each section 5 and 8 slopes oil atan angle and merges into end ilages 8, 8 which-are provided with pairs of holes 9, 9, by means of which the indicator is removably attached-to theflbfls. as

will presently be explained. i

A space separates the concealed end of the an inner section 8 from the corresponding end of the outer section 5 and w thin this space is ac- 'commodated the coil .spring'l, having-its ends I bent into hooks for attaching to the corresponding ends .of the telescoping sections. By preference, the inner telescoping section 6 carries at its free end, an arm or finger Ill arranged slightly oblique to the axis of the coil spring I and provided throughout its length with a series of holes Illa. With the several holes Illa. thus spaced, as clearly shown in Figure 3, it follows that by hooking the adjacent end of the spring into one or the other of these holes llia, it is possible to adjust the spring tension to the particular cleaner on which the indicator is to be used. The outer or free end of the spring '1 is anchored to the adjacent and of the outer section Bin any suitable manner, as for instance, by slitting and depressing a narrow strip of the metal to form a loop for the outer end of the spring 8, as shown at H inFigures2and 3.

Bearing in mind that the purpose of the indicator is to inform the operator of the operating conditions, any suitable combination or arrangement of visual signals may be utilized, as for instance, by applying the word Clean on the elevated central panel of the lower section 6 so that it .normally registers with and is visible through the rectangular opening or window 5a in the outer telescoping section, as shown at E2 in Figure 2. Also, disposed inwardly and beyond the word Clean, and toward the spring attaching end of the section 6 are printed or stamped the words Empty bag, as at l3, Figure 2. This latter indication, however, is normally concealed from view but if the sections are extended, the word Clean will be replaced by the words Empty bag within the window 50. and being seen by the operator is a warning that the bag should be emptied before further cleaning operations are carried on.

But to have the indicator function as intended, it is attached to the bag in a. particular way, namely, by having a slight excess or gathering of the bag fabric included between the points at which the ends of the indicator are fastened. Now, as clearly shown in Figure l, the indicator is arranged circumferentially of the bag and preferably on the top side thereof and adjacent its lower end, Moreover, as shown'in Figure 3, the sections of the indicator have a distinct arcuate conformation from end to end so as to conform to the rounded contour of the bag when inflated.

In order to properly locate the indicator upon the bag, pairs of fasteners l4, H are anchored to the bag material and properly located to make connection with the holes 9, 9 at each end. Thus,

- the pairs of fasteners H, 'H are arranged symmetrically with respect to a circumferential line passing around the bag, but more important, the

pairs of 'fasteners are spaced apart circumferentially a distance slightly greater than the distance between the holes 9, 9 at opposite ends of the indicator when retracted. Thus, in applying the indicator to the bag it is necessary to include a slight excess of material between the attaching points, this excess being indicated or represented in Figure 3 by the folds l5, J5.

The fasteners ll, M may be of any suitable type, as for instance of the kind resembling glove Thus, once the indicator has been attached and the spring "I properly adjusted to the pressure conditions of thebag, it follows that as long as the bag'does not become fllled with dirt to the point of reducing its filtering capacity in an excessive degree, the cleaner will operate emciently and the indicator will register .Clean. But should the bag become sofull of dirt and litter as to create a condition of excessive back pressure, this condition will be reflected in an increased circumferential expansion of the bag sufficient to overcome the tension of the spring I, thus causing the telescopic sections of the indicator to elongate and bring the warning signal Empty bag into register with the window 5a, replacing the safety signal Clean" which passes beneath the outer end portion of the outer section 5. This extension or elongation of the telescoping sections of the indicator is clearly shown in dotted lines in Figure 3, and is accompanied by the filling out of the bag material between the points of attachment.

A bag pressure indicator of the expansible' or extensible type adapted to be removably mounted upon a bag, has the distinct advantage of being relatively inexpensive'in its construction and being capable of direct application to the bag, it is possible to consider them as optional equipment since they can be provided or not, as the user may desire, without altering the design of the cleaner body. A further advantage of this particular type of indicator and a detachable mounting is the factthat it can be transferred from one bag to another as they wear out.

Having therefore set forth a practical adaptation of my invention together with the advantages thereof, I claim:

1. In an operating condition indicator for suction cleaners, the combination of a dirt receptacle of flexible material for said cleaner, a pair of extensible telescoping members attached to said receptacle in a manner such that the same tend to extend endwise and display an appropriate signal when the bag is inflated, and tension means opposing the extension of said members until the pressure in said receptacle reaches a predetermined maximum.

, 2. In an operating condition indicator for suction cleaners, the combination of a dirt bag of flexible material attached to the cleaner, an assembly of extensible parts attached to the material of the bag with suiiicient excess of such material between the points of attachment to allow for the relative displacement of the parts when said bag is inflated, tension means acting to oppose the displacement of said parts below a predetermined maximum of internal pressure within said bag, and a signal adapted to be shifted into a visible position under pressures exceeding said predetermined maximum.

3. i In an operating condition indicator for suction cleaners, the combination of a dirt bag forming a part of the cleaner assembly, a pair of endwise extensible members attached directly to the bag material with an excessthereof between the points of attachment, and a tension member connecting said extensible member and acting to oppose the extension of said members under normal operating pressures in said bag, one of said members having a normally concealed signal adapted to become visible to the operator upon the extension of said member under a predetermined increase ofpressurewithin said bag. 4. In an operating condition indicator for sucv, tion cleaners, the combination of an exposed dirt bag of a flexible material attached to said cleaner, 8. pair of endwise extensible members having telescopic connection with each other and attached at opposite ends to the bag material with sufficient excess of material between the points of attachment to allow for the extension of said members when the bag is inflated, a tension spring connecting said members and acting to oppose their relative displacement under normal operating pressures in said bag, one of said members having a signal normally concealed by a portion of the other but adapted to be uncovered in the endwise extension of said members under predetermined increased pressure conditions within said bag.

5. An operating condition indicator for suction cleaners, the combination oivan exposed fabterial between the points of attachment to allow for a limited extension thereof under the circumferential expansion of said bag in its inflated condition, said members including a safety signal adapted to be displayed under normal pressure conditions within said bag and to be reaches a predetermined maximum.

6. In an operating condition indicator for suc tion cleaners, the combination of a dirt bag attached to the discharge outlet of the cleaner, a pair of endwise extensible telescoping sections arranged circumierentially of the bag and fastened at opposite ends thereto with a predetermined excess of the bag material between the points of attachment whereby said members can be extended endwise when said bag is in inflated condition, and a spring connecting said sections together and acting togprevent their relative extension under normal operating pressures in said bag, one of said sections being provided with a warning signal normally concealed from view but adapted to be uncovered in the endwise extension of said sections of a predetermined increase in the internal pressure of said bag. 

